1. Field of the Invention
The invention relates to a grid mat with warp thread strands running at regular intervals lengthwise or in the warp direction and weft thread strands running at regular intervals crosswise or in the weft direction which are connected to the warp thread strands at the points of intersection with the warp thread strands by raschel knitting, stitching, interweaving, adhesion or welding.
2. Discussion of Background Information
Grid mats of this type are known from numerous published patent applications, including DE 20 00 937, DE 41 37 310 and DE 41 38 506.
These grid mats are produced for numerous fields of application, in particular mining and tunnel construction as a lagging mat, foundation engineering and earthwork engineering for reinforcing the ground and for securing or stabilizing slopes and for protecting from falling rocks, and in highway engineering for reinforcing the roadway surface.
Grid mats of this kind are, e.g., three to six meters wide and 20 or 30 meters long. The main direction of stress runs lengthwise or in the warp direction. However, for many applications a high load capacity in the weft direction is also necessary. Grid mats placed next to each other are connected by their edge areas overlapping and by means of threading elements, that is, rods or cords that are threaded in one or two mesh rows running lengthwise in such a way that they catch under the weft thread strands of the lower edge area and catch over the weft thread strands of the upper edge area. When tension forces acting in the weft direction act on the grid mats thus connected, the connection of the weft thread strands with the warp thread strands is strained at the points of intersection.